A long term evolution-advanced (LTE-A) communication system which can support high speed communications service over wider frequency bands than conventional LTE systems has been newly developed.
A carrier aggregation (CA) technology, which is one of key technologies of the LTE-A, is the technology which increases a system throughput by combining and operating two or more multiple unit frequency bands (component carriers, CC) thereby transmitting data using a wider bandwidth.
Therefore, as for a base station which operates with the frequency aggregation function (referred to as “CA function”, hereinafter), it can use two or more frequency bands (CC) to increase a data transmission rate in proportion to the number of used frequency bands (CC).
Meanwhile, a heterogeneous network environment has recently emerged in which various base stations forming cells of different cells coexist in the same area. In this heterogeneous network environment, since various kinds of small base stations having smaller cell coverages than conventional macro base stations can be arranged, so that they form macro cells and small cells in an area where various kinds of base stations overlap to provide wireless communication service to users.
In this heterogeneous network environment, it is common that small cells are included in a macro cell, and, therefore, the macro base station and the small base station use different frequency bands in order to avoid interference; for example, the macro base station uses an f1 frequency band while the small base station uses an f2 frequency band.
In the meantime, when macro base station and the small base station operate with the CA function in the heterogeneous network environment, an increase in a system throughput will be expected for an area in which the macro base station and the small base station coexist when the macro base station additionally uses the f2 frequency band while the small base station additionally uses the f1 frequency band.
By the way, when the macro base station and the small base station operate with the CA function in the heterogeneous network environment, there can be a case in which the increase in the system throughput due to the CA function is not obtained since the interference increases when the macro base station and the small base station use the same frequency band.
Therefore, control of the base station management as well as the CA function which are proper for the heterogeneous network environment are required in order to obtain an optimum system throughput by using the CA function in the heterogeneous network environment.